Mat section



FIG. 1 is a front, top and left side perspective view of a mat section showing my new design;

FIG. 2 is a top plan view;

FIG. 3 is a bottom plan view;

FIG. 4 is a front elevational view; and

FIG. 5 is a left side elevational view. 

The ornamental design for a mat section, substantially as shown and described. 